/*
 * Copyright (C) 2008-2014 TrinityCore <http://www.trinitycore.org/>
 * Copyright (C) 2005-2011 MaNGOS <http://getmangos.com/>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation; either version 2 of the License, or (at your
 * option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program. If not, see <http://www.gnu.org/licenses/>.
 */

#ifndef _WARDEN_BASE_H
#define _WARDEN_BASE_H

#include "ARC4.h"

#include <vector>

class BigNumber;
class ByteBuffer;
class WorldSession;

enum WardenOpcodes
{
    // Client->Server
    WARDEN_CMSG_MODULE_MISSING                  = 0,
    WARDEN_CMSG_MODULE_OK                       = 1,
    WARDEN_CMSG_CHEAT_CHECKS_RESULT             = 2,
    WARDEN_CMSG_MEM_CHECKS_RESULT               = 3,        // only sent if MEM_CHECK bytes doesn't match
    WARDEN_CMSG_HASH_RESULT                     = 4,
    WARDEN_CMSG_MODULE_FAILED                   = 5,        // this is sent when client failed to load uploaded module due to cache fail

    // Server->Client
    WARDEN_SMSG_MODULE_USE                      = 0,
    WARDEN_SMSG_MODULE_CACHE                    = 1,
    WARDEN_SMSG_CHEAT_CHECKS_REQUEST            = 2,
    WARDEN_SMSG_MODULE_INITIALIZE               = 3,
    WARDEN_SMSG_MEM_CHECKS_REQUEST              = 4,        // byte len; while (!EOF) { byte unk(1); byte index(++); string module(can be 0); int offset; byte len; byte[] bytes_to_compare[len]; }
    WARDEN_SMSG_HASH_REQUEST                    = 5
};

enum WardenCheckType
{
    // end of checks packet
    CT_END                  = 0xFF,

    PAGE_CHECK_A            = 0x27, // (B2) 178: uint Seed + byte[20] SHA1 + uint Addr + byte Len (scans all pages for specified hash)
    PAGE_CHECK_B            = 0x68, // (BF) 191: uint Seed + byte[20] SHA1 + uint Addr + byte Len (scans only pages starts with MZ+PE headers for specified hash)
    MEM_CHECK               = 0x34, // 243: byte moduleNameIndex + uint Offset + byte Len (check to ensure memory isn't modified)
    MODULE_CHECK            = 0x4E, // 217: uint Seed + byte[20] SHA1 (check to ensure module isn't injected)

    // module info
    WOWWARDEN_INFO          = 0x75, // returns 3 64bit addresses: executable, warden, main warden struct

    // no data
    TIMING_CHECK            = 0xD0, // not sure

    MPQ_CHECK               = 0x98, // 152: byte fileNameIndex (check to ensure MPQ file isn't modified)
    LUA_STR_CHECK           = 0x8B, // 139: byte luaNameIndex (check to ensure LUA string isn't used)
    DRIVER_CHECK            = 0x71, // 113: uint Seed + byte[20] SHA1 + byte driverNameIndex (check to ensure driver isn't loaded)
    PROC_CHECK              = 0x7E, // 126: uint Seed + byte[20] SHA1 + byte moluleNameIndex + byte procNameIndex + uint Offset + byte Len (check to ensure proc isn't detoured)
};

#pragma pack(push, 1)

struct WardenModuleUse
{
    uint8    Command;
    uint8    ModuleHash[32];
    uint8    ModuleKey[16];
    uint32   Size;
};

struct WardenModuleTransfer
{
    uint8    Command;
    uint16   DataSize;
    uint8    Data[500];
};

struct WardenHashRequest
{
    uint8    Command;
    uint8    Seed[16];
};

#pragma pack(pop)

struct ClientWardenModule
{
    typedef std::pair<uint8 const *, size_t> MemChunk;

    MemChunk data;
    MemChunk key;
    MemChunk seed;
    MemChunk hash;
    MemChunk serverKeySeed;
    MemChunk clientKeySeed;
    MemChunk clientKeySeedHash;
};

class Warden
{
public:
    Warden();
    virtual ~Warden() { }

    void banAccountIfNeeded() const;

    virtual void Init(WorldSession* session, BigNumber* k) = 0;
    virtual void RequestHash() = 0;
    virtual void HandleHashResult(ByteBuffer &buff) = 0;
    virtual void RequestData() = 0;
    virtual void HandleData(ByteBuffer &buff) = 0;

    void SendModuleToClient();
    void RequestModule();
    void Update();
    void DecryptData(uint8* buffer, uint32 length);
    void EncryptData(uint8* buffer, uint32 length);

    static bool IsValidCheckSum(uint32 checksum, const uint8 *data, const uint16 length);
    static uint32 BuildChecksum(const uint8 *data, uint32 length);

protected:
    // common function for packet sending
    void sendPacket(uint32 opcode, void const *data, size_t dataSize);

    WorldSession* _session;
    ARC4 _inputCrypto;
    ARC4 _outputCrypto;
    uint32 _checkTimer;                          // Timer for sending check requests
    uint32 _clientResponseTimer;                 // Timer for client response delay
    bool _dataSent;
    uint32 _previousTimestamp;
    ClientWardenModule _module;
    bool _initialized;
};

#endif
